Using acrylic gesso on different supports such as linen, wood and metal
Reader Question: Can acrylic gesso be reliably used on linen as well as cotton? How about metals or boards (and which)?
Yes, Linen Canvas can be primed with gesso just as well as cotton canvas can. Be sure to use 2 - 3 coats of gesso to ensure that the gesso fully primes the linen surface. If you would like to make the linen surface as smooth as possible, instead of brushing on the acrylic gesso you can apply the gesso with a hard, straight edge (such as a ruler or a credit card). Glide the gesso across the canvas with the ruler or credit card to essentially push the gesso into the little grooves or crevasses in the canvas. This will make the linen surface easier to work with. However, if you prefer to let the bumps of the fiber show through your painting, then you can simply brush on the acrylic gesso as normal.
Gesso can also be applied to any wooden supports, such as plywood, masonite, MDF, maple, birch, or other hardboards. If it is wooden, it will reliably accept gesso as a primer. You should apply at least 2 - 3 coats of gesso to any wooden support. If you want a smooth surface, you can lightly sand the gessoed wood with a fine-grit sandpaper in between each coat of gesso. Be sure to wipe away the loose particles with a damp cloth after you sand it.
Certain metals can also be primed with gesso, but it might be a better idea to prime them with a metal primer first (which you can purchase at your local hardware store), and then apply 2 coats of gesso. First be sure to clean/degrease the surface to remove any oils. You may also want to lightly sand the metal so that it more easily accepts the gesso.
In a pinch, non-ferrous metals (those that do not contain iron) can be coated directly with gesso. These include aluminum, titanium, copper, tin and brass. Even though it's okay to prime these metals directly with gesso, it is generally advisable to prime them with a metal primer first, and then apply 2 coats of gesso.
Ferrous metals (those that contain iron, such as stainless steel or wrought iron) will require a protective barrier between the metal and the gesso to prevent rust, so be sure to use a metal primer with rust inhibitors. After that dries you can then prime the surface with gesso.
If you want to paint on metal, there is a line of metal fine art panels produced by Duho that are already degreased, sanded and cleaned. You can get more info about how to use them on their website.
I hope that helps!